A dentist compliments the invention of anotherIn this letter dated December 5, 1842, Dr. Edwin Sercombe of London extols the virtues of his recently acquired dental "engine," a device developed by dentist and inventor James Beall Morrison. "I am daily reminded of you now," writes Sercombe, "as I use hourly that masterpiece of your brain 'the engine.'" Morrison's "engine" was the precursor to modern power-driven dental instruments.